Safety motion picture projector



June 23, 1936. H, E 2,045,022

SAFETY MOTION PICTURE PROJECTOR Filed Sept. 18, 1935 3 Sheets-Sheet l hizzeas fiss if 5 3 K5,. )VM

MJMM 2 June 23, 1936. H. w. NEPO 2,045,022

SAFETY MOTION PICTURE PROJECTOR Filed Sept. 18, 1933 3 Sheets-Sheet 2 3 4 1 ,ZFzZZIao/T gig/265565. I 19217:; Ma 1 Z20. ,r

June 23, 1936. V H. w.

SAFETY MOTION P Filed Sept. 18, 1933 'IIIIIIIIII I! WEI NEPO 2,045,022

ICTURE PROJECTOR 3 Sheets-Sheet 3 moving the above pointed out dangers.

Patented June 23, 1936 UNITED STATES PATENT OFFICE Barry W. Nepo, Chicago, Ill. Application September 18, 1933, Serial No. 689,816

7 Claims.

My invention relates to safety motion picture projectors and has for an. object the perfection of the motion picture projector which will be safe in operation and will reduce the fire hazard.

As it is well known the arc lights employed in motion picture projectors generate a ray of terrlfic heat when used in conjunction with the customary condensing lenses now employed. The ray of some popular types of projectors is 900 degrees Fahrenheit at the aperture plate, and consequently any stoppage of the film in this location is likely to cause the ignition of the film. It is now customary to employ a separate circuit for the are light and a separate circuit for the driving mechanism of the projector. The reason for this lies in the fact that it takes a considerable amount of time for the are light to become sufficiently warm for proper operation. If this were not the case the changing of a roll of film would entail a long delay until the are light had been returned to proper I working condition. If the circuit which drives the driving mechanism becomes disabled, the film will be stopped but the beam from the are light will continue to shine through the film. If this continues for any length of time the film will be ignited, and the fire will spread to the roll contained in the feeding magazine. If a belt on the feeding or take-up mechanism should become broken, the same result would follow, and the main object of my invention is to eliminate the dangers caused by these difiiculties.

Sometimes the film is broken during projection and of course accumulates within the projector housing while the driving mechanism continues in operation, and since the film is not passing the aperture plate with sufficient rapidity there is danger of ignition. I propose to eliminate the great danger occasioned through breakage by preventing the spread of the flame from the projection housing.

Some safety devices have been provided heretofore but they have not been effective in re- Some have employed a knife for cutting the film when fire starts within the projector housing, but even if this type of mechanism accomplishes its full purpose the dangers are not entirely removed. I propose to minimize the dangers to the greatest possible extent and at the same time leave the projecting mechanism in such condition that it may be operated in the customary manner, and' in addition propose to provide mechanism which will stay in proper working order over a long period of time.

Other objects will appear hereinafter.

My invention may be best understood by reference to the accompanying drawings in which:

Fig. l is a side elevational view of the front portion of a, projecting machine, viewing the device from the left side and illustrates part of my safety mechanism;

Fig. 2 is a side elevational view of the main projector housing viewed from the right hand side and illustrates the remaining parts of my safety mechanism; the side cover plate has been removed from the projector housing;

Fig. 3 is a detailed view taken substantially on line 33 of Fig. 1 and illustrates the shutter for the are light housing and my mechanism for operating the same;

Fig. 4 'is a detailed view taken substantially on line 4-4 of Fig. 2 and illustrates parts of the mechanism employed for closing the fire gates;

Fig. 5 is a detailed view taken substantially on line 5-5 of Fig. 2 and illustrates part of the mechanism employed for closing the lower fire gate;

Fig. 6 is a detailed view taken substantially on line 6-6 of Fig. 2 and illustrates part of the 20' mechanism employed for breaking the projector driving circuit when fire breaks out within the projector housing.

Although my safety mechanism may be employed with many types of projectors, I have shown it attached to a machine somewhat diagrammatically illustrated.

As can be seen from Fig. 1 the projecting machine shown comprises an are light housing I 0, an eye shield ll, aperture plate l2, maimprojector housing l3, feeding magazine l4, main' power and driving'mechanism l5, and take-up magazine 16.

Refen'ing now to Fig. 2, the interior of projector housing l3 contains feeding sprocket l1, locking roller l8, inner gate l9, intermittent sprocket 20, locking guide 2|, take-up sprocket 22, housing sleeve 23, lens holder 24, feeding slot 25, and take-up slot 26. The main power shaft 21 transmits power to feeding sprocket IT, intermittent sprocket 20, and shutter shaft 28 through appropriate gear and shaft mechanism. Take-up shaft 29 is driven by take-up belt 30 and transmits power to take-up sprocket 22.

Referring now to Fig. 1, take-up belt 30 drives a pulley 3| which is keyed to a shaft 32 for the purpose of driving take-up magazine I 6. Power is taken from a motor 33 by belt 34 from pulley 35, and. belt 34 transmits power to pulley 36. Shaft 31 is keyed in pulley 38, and a gear 38 is keyed to shaft 31. A fly wheel shaft 39 has a fiy wheel 40 and gear 4| keyed thereto. Gear 4| meshes with and is driven by gear 38, and gear 38 in turn drives gear 42 which is keyed to shaft 43. Gear 44 is keyed to shaft 43 and drives gear 45 whichis keyed to shaft 29. Gear 45 then drives pinion 46 which is keyed to shaft 21 and cooperates with mechanism heretofore described for driving intermittent sprocket 20, feeding sprocket l1, and shutter shaft 28.

Referring now to Fig. 2, the upper end of projector housing I3 terminates as at 41 and has its upper wall cut away for part of its width for the reception of removable flre gate 48. Fire gate 48 has end walls 49 and 68, lower wall 5i having film slot 52, and the lower wall 5| also has an arcuate portion 53. The end walls 49 and 58 are provided with dowel pins 54 and 55 which seat securely in appropriate slots in the end walls of projectors housing I3. Referring now to Fig. 4, the bottom wall 5| is secured to side walls 56 and 61 by screws 58 and slidably supports a slidable block 59. End wall 49 is secured to side walls 56 and 51 by appropriate bolts 68 and thus limits longitudinal movement of block 59. The side wall 56 is provided witha longitudinal bore 6| for the reception of wiring later to be described, and side walls 56 and 51 are provided with appropriate transverse bores 62 so as to provide bearings for cam shaft 64. Block 59 is provided with an arch-shaped transverse cut away portion 65 which receives a transversely extending cam shaft 64 and cam 66. Spacing collars 61 space cam 66 centrally of block 59 and equidistant side walls 56 and 51. Referring again to Fig. 2, the inner end 68 of block 59 is arcuate in cross-section and adapted to conform exactly to the arcuate inner end 69 of stationary block 18. The outer end of block 18 which is above arcuate bottom wall 53 is cut away and provides open space H which is rectangular in cross-section and adapted to provide space for mercury switch 12. A switch bracket 13 is provided on the bottom wall of space H and pivotally receives a pin 14 which extends transversely out and supports mercury switch 12. The pin 14, however, is not pivotally mounted in regard to switch 12 and link 15 because it is necessary for link 16 to cause the rotation of switch 12 when link 16 is moved in a longitudinal direction. A vertical link 11 is pivoted to link 16 and also pivotally supported on the lower wall of space 12 by a bracket 18. Link 11 extends entirely through the lower wall of block 18 and is pivotally connected as at 19 to a strip of thermo-responsive metal 88 whose opposite end is secured by screw 8| to the lower face of block 18. The strip 88 substantially conforms in shape to the arcuate portion 53 and serves as a guide for the upper loop of film 83. Switch 12 has a pair of spaced contact members 84 and to which wires 66 and 81 respectively are secured, and the said wires pass longitudinally through bore Si in side wall 56.

The outer end of shaft 64 to the right, as shown in Fig. 4, is anchored in a bearing 88 which is secured to upper end wall 89 of projector housing I3, and a small arm 98 is keyed to said shaft. Between arm 98 and bearing 88 a second arm 9i is keyed to shaft 64 and extends substantially horizontally as can be seen clearly in Fig. 1 to a link 92 with which it is pivotally connected. Link 92 in turn is pivotally connected with a vertically extending rod 93 which is received in a vertical cylindrical sleeve 94 which is integral with a cap secured to a solenoid generally indicated at 96. A collar 91 ispinned to rod 93 and serves as a stop for coil spring 98. The other end of coil spring 98 abuts against a stop 99 which is fixedly secured to sleeve 94 by a set screw I88. Rod 94 is slidably received by stop member 99 and extends inwardly of the solenoid bore -I8I. The solenoid is provided with appropriate windings I82, and a pair of cores I83 are fixed to red 94. A lower sleeve I84 of cap I85 supports a guide I86 for rod 94. Insulated brackets I81 support the'solehold 96 on the front wall of projector housing I3. Terminals I88 and I89 are connected to wires 81 and II 8 respectively. The opposite end of wire H8 is connected to one terminal of a manually operable switch I31.

The opposite end of shaft 64 as shown in Fig. 4 particularly and also in Fig. 2 has an arm III keyed thereto and extending in a substantially horizontal direction. A vertical connecting link H2 is pivotally connected to arm I I I at its upper end and pivotally connected to arm H3 at its lower end.

A lower fire gate H4 is removably received in the lower part of projector housing I3 and retained in place by dowel pins H5 in the lower wall of the projector housing. Fire gate H4 has an upper wall H6 as can be clearly seen in Fig. 2 and is secured to removable end wall H1 by appropriate screws and also secured to stationary end wall H8 in the same manner. A removable lower wall H9 is secured to stationary block portion I28 and to removable end wall I I1 by appropriate screws. Stationary block portion I28 is cut away to provide space I2I for mercury switch I22. A bracket I23 is secured to the lower wall of 5 space I2I and supports switch I22 by a pivot pin- I24. Pin I24 is not pivotally mounted as to switch I 22 or arm I25 for the rocking motion of arm I25 by a pivotally connected link I26 must cause the rocking of switch I22 on the axis of pin I24. A bell crank I21 has one leg thereof pivotally connected to link I26, and the bell crank I 21 is pivoted to a depending bracket I28 mounted on the lower face of upper wall H6. The horizontal leg of hell crank I21 is pivotally connected to a vertically extending link I29 which extends through an appropriate opening I38 in upper wall H6. The upper end of link I29 is secured to one end of a substantially U-shaped piece of thermo-responsive metal I3I whose side members lie in horizontal planes as can be clearly seen in Fig. 6. The lower side member of member I3I is secured to a vertical bracket I32 which is attached to the upper wall H6. As can be clearly seen from Figs. 2 and 5 the stationary block portion I28 is substantially U-shaped in plan section at the end opposite the space I2I, and thus it provides longitudinally extending side walls I 33 and I34. Wall I33 has a longitudinal bore I35 which communicates with an aperture I36 in removable end wall II1. Wires 86 and I38 are reeeivedthrough aperture I36 and extend through bore I35 to space I2I where they are connected to the contacts I39 and I48 of switch I 22. The opposite end of wire I38 is secured to one terminal of a manually operable switch I31 whose opposite terminal is connected to one wire of the main power line. Substantially centrally of block I28 and between longitudinally extending side walls I33 and I34 is provided a vertically extending arcuate transverse wall I4! from which a slidable block I42 is spaced as shown in Fig. 2. The inner end wall of slidable block I 42 is arcuate in crosssection and meshes precisely with the arcuate wall I4I of stationary block I28. The upper plate H6 is provided with a transverse slot I 43, and the lower wall I I 9 is provided with a slot I44, and film 83 passes through slot I 43 between slidable block E42 and arcuate wall I, and thence through slot I44 to take-up slot 26. The spaced side walls I33 and I34 provide a longitudinal slot I45 for block I42. Block I42 has a vertical arch-shaped slot I 46 in which a cam I41 operates. As can be seen clearly in Fig. 5 cam I41 is keyed to transverse shaft I48 whose ends bear in appropriate bores in side walls I33 and I34 of stationary block I20. centrally in slot I45. The outer left end of shaft I48 as seen in Fig. 5 has arm II3 keyed thereto, and as before stated the opposite end of arm H3 is pivotally connected to link II2.

Referring now to Fig. 1, an idling roller I50 rides on belt 34 and is pivotally connected to a yoke I5I whose lower end is keyed to transverse pin I52 which extends between the vertical side wall of a switch box I53. Switch box I53 is secured by bracket I54 to supporting frame I55. Interiorly of switch box I53 an L-shaped contact member I56 is secured to insulating material I51 which in turn is keyed to transverse pin I52. A stationarycontact member I58 is secured to the bottom wall of switch box ,I53 and has a wire I59 connected thereto. The opposite end of wire I59 is conpected to one terminal post of the main line switch 22I.

A similar idler'roller I6I rides on take-up-belt 30 and is pivotally mounted in a yoke I62. The lower end of yoke I62 is keyed to pin I63 whose ends are pivoted in the side walls of a switch box I64. A piece of insulating material I65 is also keyed to pin I63 and has an L-shaped contact member I66 secured thereto for contact with lower contact member I61. Wire I68 is connected to contact I61 and contact I56.

Solenoid I1I comprises a winding I12, cap sleeves I13 and I14, and a rod I15 is slidably received in sleeves I13 and I14. A guide collar I 16 is pinned to rod I15 and acts as a stop member for a spring I11. A movement limiting guide collar I18 is securely fixed to sleeve I13 by set screw I19 and acts as a stop abutment for compression spring I11. A pair of cores are mounted on rod I15 and are similar to cores I03. An attaching strap bracket I encircles winding I12 and is fixed on supporting frame I 55.

Above solenoid "I a magnetic brake frame I8I is fixed on supporting frame I55 and is somewhat rectangular in form. Between its opposite vertical sides andslidably mounted in hearings in Said side members is a brake shaft I82 carrying a brake shoe I83 for action on fly wheel 40. A stop collar I84 is pinned to shaft I82 between vertical side members of frame I8I and acts as an abutment for a compression spring I85. The opposite end of spring I85 abuts against one of the side members of frame I8I and serves to urge brake shaft I82 to the left as shown in Fig. 1. Outside the limits of frame I8I a pivot pin I86 extends transversely through shaft I82 and sup ports a link I81. The opposite end of link I81 is pivotally connected with the upper leg of a bell crank I88 whose knee is pivoted to a depending bracket I89 carried by frame NH. The lower leg of bell crank I 88 is pivotally connected to a link I90 ,whose opposite end is pivoted on rod I15.

The upper throw-out switch I93 comprises a housing I94, slidable contact member I95 actuating rod I96 carrying horizontally extending spring guide I91 and compression spring I98. The actuating rod I96 has an offset portion which seats against one side wall of switch box I94 and also has a vertically extending ofi-set portion adjacent spring guide rod I91 for the seating of spring I98. The protruding end of rod I96 extends to a point adjacent arm 90 mounted on shaft 64 and is in position to be moved horizontally by the movement of arm 90. The opposite end of spring I98 seats against the opposite sid'e wall of switch box I94. A lower contact member I99 extends Spacing collars I49 keep cam I41 spacedtact I95 is adapted to slide over plate 280 and close a circuit between said plate and contact member I99. The wire I69 electrically connects contact I 99 and terminal I66 of switch I 64. A wire 20I electrically connects plate 200 to terminal 202 of motor 33. Between contact plate 200 and motor 33, however, a shutter operating wire is interposed.

A wire 203 is connected with wire MI and electrically connects terminal 205 of solenoid 206 to contact plate 200 through wire 20I. ,A switch 204 is interposed electrically between wire MI and terminal 205. The solenoid 206 is supported by suitable bracket 201 mounted on front of are light housing l0, and the construction of the solenoid is analogous to that of solenoid HI and solenoid 96. The upper end of its actuating rod 208 is pivotally connected to link 209 whose opposite end is pivotally connected to the lower end of the offset bell crank 2 I 0. The knee of bell crank 2I0 is pivoted on vertical bracket 2, and the upper leg of the bell crank is pivotally connected to the connecting link 2| 2. The opposite end of link 2I2 is pivoted on an arm 2I3 which is in turn keyed to a pin 2. Pin 2I4 passes through an appropriate aperture in 8. lug 2I5 carried by disclike shutter 2 I 6 and has its opposite end pivoted in shutter carrying bracket 2I1. on the front of are light housing III. The pin 2 I4 is also keyed to the lug 2I5 so that rotational movement of the pin 2I4 will carry with it shutter 2I6. The other contact member 2I8 of solenoid 206 is connected by wire 2I9 to terminals 220 of main knife switch 22I in the main power line. Wire I92 connects wire 2I9 to terminal I10 of solenoid I1 I, and wire 222 connects wire 2I9 to terminal I 60 of motor 33. Wire 223 connects wire 20I to terminal I9I of solenoid Ill.

The operation of the device will now be set out in detail. When the operations for the day are over, switches I31 and 22I are opened, and thus current is disconnected from motor 33 and all the rest of the mechanism shown particularly in Fig. 1 and all the mechanism shown particularly in Fig. 2. When switch 22I is opened the magnetic force of solenoid "I is of course removed and compression spring I11 acts against collar I16 to force rod I15 vertically against bell crank I88, link I81, and brake shaft I82, and the tension of compression spring I85 against stop collar I84 causes brake shoe I83 tobe applied to fly wheel 40 in order to stop the driving mechanism connected withfly wheel 40. At the same time a similar action occurs in regard to solenoid 206, and rod 208 is moved vertically as shown in Fig. 8 by the action of its compression spring against its lower stop collar, and rod 208 pushes upwardly on link 209 and the lower leg of bell crank 2I0 to cause link 2IZ to be moved tothe left and carry with it arm 2I3, and shutter 2I6. The shutter 2I6 closes the are light opening and prevents the are light from shining through its opening. I

On the other side of the machine as shown particularly in Fig. 2 the opening of switch I31 causes solenoid 96 to be demagnetized, and compression spring acting against collar 91 forces rod 93 upwardly to impingeagainst link 92 and force arm 9| upwardly. Since arm 9| is keyed to shaft 64 and cam 66 is likewise keyed thereto, the eccentric part of the cam will be forced to the left as shown in Fig. 2. The force of the eccentric portion of cam 66 against the left side wall of arch-shaped opening 65 will cause slidable block 59 to move to the left and cause its inner arcuate end 68 to come in close contact with the similar arcuate wall member [8 and close the exit from the projector housing I3. The film 83 at this time is pressed very tightly between member 59 and member 18, and there is no danger of a spreading of fire from the projector housing l3.

To the opposite end of crank shaft 54 is keyed the arm III which moves upwardly as arm 9| moves upwardly and carries with it link I i2 which raises arm H3. The arm H3 is keyed to shaft I48. and the rotation of shaft I48 as seen in Fig. 2 in a counter-clockwise direction causes movable block I42 to slide to the left and close the opening from the lower wall of the projector housing in a manner analogous to that explained in regard to the upper fire gate.

When switches I31 and ZZI are closed the solenoids 96, 208, and I'll are energized, and the movements are in the reverse direction. If the switches just described are closed and fire should break out within the projector housing and heat thermo-responsive strip 80, it will expand as contacts I39 and I48.

shown in Fig. 2 and cause vertical link H to r0- tate in a clockwise direction and cause the mercury in switch 12 to move to the opposite end from contacts 84 and 85 and break the circuit to solenoid 98. When this happens the upper fire gate and lower fire gate will be closed, and the upward movement of arm 9| will cause arm 90 as shown particularly in Fig. l to move to the right against actuating rod I96 and thus break the circuit between contact I99 and plate 208. Then solenoids Ill and 206 will be deenergized, the brake applied to the fly wheel, and the shutter 2H5 closed. Likewise, the entire driving circuit is broken, and the driving mechanism will of course stop. An analogous operation occurs if the lower loop of film 83 passing through U- shaped thermo-responsive metal strip I3I becomes ignited and causes link I29 to be drawn upwardly so as to cause the mercury to leave the If belt 30 should break, the idling roller I GI will descend by gravity and raise contact I68 from contact I61 and break the circuit from the main switch ZZI through wire I59, switch I53, and wire I58 to wire I69. When the circuit through switch I84 is broken, solenoids 206 and HI are deenergized, the magnetic brake applied, and a shutter placed over the opening from are light housing. However, if belt 34 breaks, roller I50 on yoke I5I descends by gravity and breaks the circuit from switch 22I through switch I53 to wire I68 by raising contact member H56 from contact member I51. When this occurs, solenoids HI and 286 are deenergized, the brake applied, and the shutter closed, as above explained in connection with switch I64.

While I have illustrated and described the preferred form of construction for carrying my invention into effect, this is capable of variation and modification without departing from the spirit of 1. Projecting mechanism comprising a projector housing having a film entrance slot and a film exit slot, fire gates adjacent each of said slots, said fire gates each comprising a fixed block and a slidable block adapted to firmly clamp the interposed portion of the film between them, mechanism for driving film through said housing, cams for actuating said slidable blocks to close the film slots in said housing, means for stopping said driving mechanism, and means responsive to heat within said housing for causing the actuation of said cams for closing said openings in said housing and also for actuating said means for stopping said driving mechanism.

2. In projecting mechanism having driving mechanism therefor including a driving belt, a combination of means in contact with said driving bolt, with means for causing the stopping of said driving mechanism when said driving belt is broken, said last mentioned means comprising a brake adapted to be set when said driving belt is broken.

3. In projecting mechanism having driving mechanism therefor including a driving belt, a combination of means in contact with said driving belt, with means for causing the stopping of said driving mechanism when said driving belt is broken, said last mentioned means comprising a brake adapted to be set when said driving belt is broken, and electro-magnetic means wired in series with the driving motor of said driving mechanism for maintaining said brake in a released position.

4. A device as set forth in claim 1 in which the blocks forming the fire gates are of considerable thickness and their cooperating faces are concave and convex respectively, substantially as described.

5. In a projecting mechanism, a main housing having a film slot, film actuating mechanism, a fire gate adjacent said film slot and adapted to be closed upon failure of the film actuating mechanism or ignition of the film, said fire gate comprising a fixed block and a slidable block, a cam for moving the movable block, spring actuated means for actuating said cam, a solenoid normally holding said cam actuating mechanism retracted and adapted to release the same upon deenergization of the solenoid, and a thermostatically actuated switch for breaking the circuit to said solenoid.

6. A device as set forth in claim 5 further characterized by means actuating said gate closing mechanism for breaking the circuit to the film feeding mechanism, substantially as described.

'7. In a projecting mechanism, a main housing having a film inlet slot and a film exit slot, film actuating mechanism, a fire gate adjacent each of the film slots and adapted to close upon failure of the film actuating mechanism or ignition of the film, said fire gates each comprising a fixed block and a sliding block adapted when'actuated to clamp the interposed portion of the film between them, a cam for actuating each of said slidable blocks, spring actuated mechanism for actuating one of said cams, a solenoid normally holding said cam actuating mechanism retracted and adapted to release the same upon de-energization of the solenoid, a thermostatically actuated switch for breaking the circuit to said solenoid, and a connection between said cams whereby the actuation of one cam will cause the actuation of the other, substantially as described.

HARRY W. NEPO. 

